You know, when I look at a pika, poisoning it isn’t the first thing I think about. I think about giving it cuddles, I think about giving it scritches, and yes, I might also consider building it a tiny home with a tiny bed in a tiny city where all of its friends can live nearby in tiny homes of their own that I would also consider building. Once everyone’s moved in, I probably wouldn’t plan a mass eradication program that would leave all of those tiny homes vacant. I don’t want a tiny pika ghost town.
Fortunately, I’m not the Chinese government, so making pika ghost towns for the perceived good of my people is not something I’m likely ever going to have to consider. But for more than 50 years, that’s what’s been going on, and now researchers from Arizona State University have figured out that it’s actually just not a very good idea.
About 20 percent of the world’s population relies on the water that drains off from and runs underneath the land of the Qinghai-Tibetan Plateau (QTP). Often referred to as ‘the Water Tower of Asia,’ this 2.5 million km2 region is the origin point of 10 major rivers that flow into India, Bangladesh, China, Nepal, Pakistan, Thailand, Myanmar, and Vietnam, making it one of the largest sources of fresh water on the planet.
In the vast alpine meadows that make up 70 percent of the QTP, by far, the most abundant creature is the plateau pika (Ochotona curzoniae), a fat little guy with a thick, tawny coat and a body that will only ever grow to 140 grams in weight. These adorable natives dig into the QTP to set up their large underground warrens, and in some places, this land will harbour more than 74 individual pikas per hectare.
Because of this saturation, the plateau pikas have been classified them as pests by the local Chinese authorities - they often refer to them as ‘rats’ - and their large numbers have been blamed for the increasingly degraded landscape they live on. In reality, domestic animals have been overgrazing in the area, which led to its degradation, which in turn made it more suitable for pika burrows, so they all moved in.
If you’re a wild animal, the last thing you want to be classified as is a pest, because terrible things can happen to you when you are. Several decades ago in Australia, emus were classified as pests, and the Australian Army was tasked with destroying entire mobs of them with machine guns. In some areas of Australia, our native dog, the dingo, has been classified a pest and is culled and strung up on poles. For pikas, their pest status has led to mass eradication by poisoning.
The poisoning began in 1958, and first became widespread in 1962, as local authorities applied zinc phosphate - a potent rodenticide - to the area. According to Maxwell Wilson and Andrew Smith from Arizona State, by 2006, an area of 357,060 km2 had been poisoned in Qinghai province alone - a project that cost almost $100 million to complete. By 2013, the researchers report, 78,500 km2 of land had been poisoned, specifically for the eradication of pikas, at a cost of $25.5 million, and over 31,000 km2 were targeted for extermination this year.
And yet, five decades of poisoning and eradication later, the condition of the land has not improved. In fact, it's getting worse. And pikas are actually just an indication of the problem, not the cause, Wilson and Smith reported in the journal AMBIO last month. Rather than blaming the plateau pika for the damage and treating it as a pest, they say, it should be considered a ‘keystone species’ of the local QTP ecosystem.
The first reason for this is the home-sharing that the pikas unwittingly facilitate on the QTP. Pika warrens are incredible. With an average length of 13 metres and a maximum length of 20 metres, these huge burrow complexes can occupy areas of over 160 m2. They’ll usually include five or six openings of up to 12 centimetres in diameter, and one nest burrow, hidden almost half a metre below the surface. These things are amazing, and when a pika family moves out of one, the nearby birds and lizards don’t hesitate to make use of it.
“These high plateau meadows support few trees, thus most endemic plateau birds (eg. snow finches Montifringilla spp.; Tibetan ground-tit Pseudopodoces humilis) breed almost exclusively in pika burrows,” Wilson and Smith report. “When pikas are poisoned, their burrows collapse and these bird species disappear or their populations are greatly reduced.”
Wilson and Smith also found that plant species richness was actually higher in pika colonies, compared with the poisoned, pika-less sites, and that they are the main food source of nearly every mammalian and avian carnivore on the QTP. "As the carnivore guild suffers in areas where pikas have been poisoned, there have been concomitant knock-on effects to human populations,” they write. "For example, with pikas making up as much as 60 - 78 percent of the diet of brown bears (Ursus arctos) on the QTP, bear attacks on property (primarily homes of local nomads) have increased where pikas have been eliminated."
So pikas are pretty important to the area, and not just because they actively support dozens of endemic plant and animal species. What Wilson and Smith also found is that their digging ways actually help the spread of water through the land, which in turn reduces instances or erosion, particularly during the summer monsoonal storms.
They figured this out by measuring the water infiltration rate in three types of treatment site - next to an active pika burrow entrance; between two or more active pika burrows, but at a distance of at least 1 metre from an active burrow entrance; and sites where pikas had been eradicated due to poisoning, and having been absent for more than two years, their burrows have collapsed. Measurements were taken at five localities spread broadly across Qinghai Province in the Sanjiangyuan region, which serves as the origin for the Huang, Yangtze, and Mekong rivers.
The lowest water infiltration rates they found were consistently recorded at the poisoning sites, and the highest rates were found at sites right next to burrow openings. Intermediate measurements were taken at sites between pika burrows. "These data confirm that through its burrowing activity, the plateau pika is an ecosystem engineer; the infiltration rate of water was consistently higher in areas occupied by pikas," the pair report.
The pikas are even helping to fight erosion in the area, despite assumptions to the contrary, Wilson and Smith explain. They suggest that on pika-occupied sites, the increased water infiltration could cause less runoff on the plateau during the intense monsoonal summer rains, which should curb the potential for water erosion on the slopes.
But the local authorities believe that the pikas' burrowing activity actually leads to increased erosion, but with little evidence to support the claim. "The assumption of increased erosion is then given as a further justification for controlling plateau pikas," the pair report. "In none of these cited papers is erosion defined, and none of them offers any experimental evidence for the claim that the presence of pikas leads to increased erosion.”
So what can be done to save the plateau pikas - which, it should be said, are still thriving as a species, despite extensive eradication programs - from so much pointless death? While Mongolian authorities have stopped poisoning pikas because of the advice of scientists, the Chinese authorities continue to ignore both local and international scientists who have been telling them that pikas aren't to blame for the damage to the QTP. But why?
Back in 2006, Smith teamed up with biologist Peter Zahler from the US Wildlife Conservation Society and vertebrate pest expert, Lyn Hinds, from Australia's CSIRO, to figure out why there's such as disconnect between the views of local policy-makers on pikas and those held by conservation scientists.
Publishing in the journal Conservation Biology in Asia, they were careful to note that this problem isn't just confined to China. In the US, another very charismatic grassland creature, the black-tailed prairie dog (Cynomys ludovicianus), has been systematically poisoned across nearly 95 percent of its former range.
"Decades of focused research has shown that prairie dogs are extremely important to grassland biodiversity, and in many locations prairie dogs actually improve forage for wildlife and livestock," they report. "Yet prairie dog poisoning continues to be an important and strongly supported policy. For example, despite significant national and international issues to discuss, the 2004 US Senatorial race in South Dakota became a sparing match between Democrat Thomas Daschle and Republican John Thune over who hated prairie dogs the most and who would most effectively oversee their poisoning."
How could anyone hate prairie dogs? They do jump-yips, for god's sake.
Smith, Hinds, and Zahler suspect that the continued poisoning stems from all kinds of problems, from long-held cultural beliefs about the role of 'pests' in land degradation, to the intense pressure the local authorities are under to do something - anything - immediately, to fix the degradation of such a crucial region, regardless of whether it's scientifically backed or not. With the roots of the problem being so complex, the solution will be equally so, but the team suggested that the Mongolian example could be a big help.
"If conservation scientists wish for their research to inform policy, they must actively work to reach out to policy makers," they wrote. "Scientists must take the next step of reaching out to policy makers through workshops, conferences, reports, and even community outreach and education to create a well-informed public who will encourage and support changes to public policy.... If we cannot learn to do this, then the value of our work for society will continue to be ignored."
It won't be easy, but the scientists do have one thing on their side, besides, you know, actual science. Plateau pikas are ridiculous. Just look at those fat little faces. You couldn't ask for a more adorable and sympathetic face to fight for. Look at it:
* All images by David Blank and used under the Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License. View more of his pika photos here.